I wish someone would tackle a live action Robotech or Battletech.
As much as I'd like to see a live action BattleTech, I'd much rather see Battle Angel Alita brought to the big screen. The setting and premise of it are IMO better fleshed out than the BattleTech universe. I'm a big fan of the BattleTech miniatures game (play it monthy) but I'm not convinced any writer they get would fill in the necessary gaps and do it any justice. And good lord, any story they did come up with would have to be heaps better than the craptastic BattleTech cartoon from the 90's.
A Robotech live action is actually already under way - from the robotech wiki:
Proposed live-action film
On September 7, 2007, The Hollywood Reporter stated that Warner Bros. had acquired the film rights to Robotech and would be producing a live-action film with an as-yet-unknown release date. Tobey Maguire is producing the film through his Maguire Entertainment banner and is pursuing the lead role in what the studio plans on being a tentpole science fiction franchise.
We are very excited to bring Robotech to the big screen. There is a rich mythology that will be a great foundation for a sophisticated, smart and entertaining film.
—Tobey Maguire, 
In an interview, Harmony Gold representative Kevin McKeever said that Warner Brothers had approached Harmony Gold about the project, that Harmony Gold would have "a say" in its creative direction, and that it was not expected to affect the production schedule for Shadow Rising. He was unable to confirm any details of budget, casting, expected release date, or storyline, explaining that it was too early in the life of the project for these things to have been decided.
How much you get excited about it probably depends a lot on how much you like Tobey Maquire. I'm still not sold on how well it will work as live action, and despite preferring traditional animation to CGI, I'd rather it be done as CGI as opposed to live action.